The fluoroquinolone derivatives which form the subject of the present invention are widely known for their antimicrobial activity:
BE 870,576; U.S. Pat. No. 4,448,962, DE 3,142,854; EP 47,005; EP 206,283; BE 887,574; EP 221,463; EP 140,116; EP 131,839; EP 154,780; EP 78,362; EP 310,849. PA0 1/--immunosuppressed rats receiving doxycycline throughout the study period (four weeks), PA0 2/--immunosuppressed rats receiving doxycycline only during the first two weeks of the study. PA0 1/--the product under study (50 mg/kg) twice daily intraperitoneally during 14 days; PA0 2/--the product under study (100 mg/kg) twice daily intraperitoneally during 14 days.
Pneumocystis carinii is a ubiquitous microorganism capable of infecting many mammals.
In particular, in immunosuppressed humans, it is the source of severe hypoxaemia-inducing pneumonia, which is fatal in the absence of treatment.
Pneumonia caused by Pneumocystis carinii occurs in subjects such as premature infants or those suffering from a severe chronic disease, and older children or adults suffering from cancer or from hematological malignancies (leukosis, Hodgkin's disease) subjected to prolonged corticoid therapy or to an immunosuppressive treatment. Pneumonia caused by Pneumocystis carinii is, in effect, the commonest opportunistic infection of AIDS and is responsible for a high mortality rate in patients suffering from this disease.